U.S. patent number 5,864,358 [Application Number 08/667,654] was granted by the patent office on 1999-01-26 for method for switching programs in digital broadcasting and digital broadcast receiving apparatus.
This patent grant is currently assigned to Matsushita Electric Industrial Co., Ltd.. Invention is credited to Souichirou Katsuki, Masashi Kubota, Toshirou Nishio, Hidekazu Suzuki.
United States Patent |
5,864,358 |
Suzuki , et al. |
January 26, 1999 |
Method for switching programs in digital broadcasting and digital
broadcast receiving apparatus
Abstract
According to the present invention, a method for switching
programs in a digital broadcasting is provided. In this method, on
a transmission side, a physical channel number for transmitting a
program having a program number therethrough is assigned to a part
of the program number. On a receiving side, in changing program
numbers from a first program number to a second program number, a
second physical channel number, for transmitting a second program
having the second program number therethrough, is identified based
on the second program number; wherein it is determined whether or
not the identified second physical channel number is the same as a
first physical channel number which is now being received; and
wherein if it is determined that the first and the second physical
channel numbers are not the same, switching is performed for
receiving the physical channel having the identified second
physical channel number.
Inventors: |
Suzuki; Hidekazu
(Yamatokoriyama, JP), Nishio; Toshirou (Hirakata,
JP), Katsuki; Souichirou (Katano, JP),
Kubota; Masashi (Kobe, JP) |
Assignee: |
Matsushita Electric Industrial Co.,
Ltd. (Kadoma, JP)
|
Family
ID: |
26486010 |
Appl.
No.: |
08/667,654 |
Filed: |
June 21, 1996 |
Foreign Application Priority Data
|
|
|
|
|
Jun 26, 1995 [JP] |
|
|
7-159111 |
Nov 1, 1995 [JP] |
|
|
7-284767 |
|
Current U.S.
Class: |
725/142;
348/E5.108; 348/E5.005; 370/486; 348/731; 725/139 |
Current CPC
Class: |
H04N
21/426 (20130101); H04N 21/44222 (20130101); H04N
21/4667 (20130101); H04N 21/4384 (20130101); H04N
21/4345 (20130101) |
Current International
Class: |
H04N
5/00 (20060101); H04N 5/44 (20060101); H04N
007/10 () |
Field of
Search: |
;348/10-11,7,12,13,705
;370/486 ;455/4.1,6.1,6.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Kostak; Victor R.
Attorney, Agent or Firm: Renner, Otto, Boisselle &
Sklar, P.L.L.
Claims
What is claimed is:
1. A method for switching programs in a digital broadcasting
wherein, on a transmission side, a physical channel number for
transmitting a program having a program number therethrough is
assigned to a part of the program number,
and wherein, on a receiving side, in changing program numbers from
a first program number to a second program number, the method
comprises the steps of:
identifying a second physical channel number, for transmitting a
second program having the second program number therethrough, based
on the second program number;
determining whether or not the identified second physical channel
number is the same as a first physical channel number which is now
being received; and
if it is determined that the first and the second physical channel
numbers are not the same, switching so as to receive the physical
channel having the identified second physical channel number.
2. A method for switching programs in a digital broadcasting
wherein, on a transmission side, a physical channel number for
transmitting a program having a program number therethrough is
assigned to a part of the program number,
and wherein, on a receiving side, in changing program numbers from
a first program number to a second program number, the method
comprises the steps of:
identifying a second physical channel number based on the second
program number, for transmitting a second program having the second
program number therethrough;
determining whether or not the identified second physical channel
number is the same as a first physical channel number which is now
being received;
switching so as to receive the physical channel having the
identified second physical channel number, if it is determined that
the first and the second physical channel numbers are not the
same;
extracting a program map table packet identifier corresponding to
the second program number from a program association table
including the second program number;
extracting an elementary packet identifier corresponding to the
second program number from a program map table including the
extracted program map table packet identifier; and
extracting a packet having the extracted elementary packet
identifier from a transport stream.
3. A method for switching programs in a digital broadcasting
wherein, on a transmission side, a physical channel number for
transmitting a program having a program number therethrough is
assigned to a part of the program number and program association
tables of all physical channels are transmitted as private data to
transport streams of all of the physical channels,
and wherein, on a receiving side, in changing program numbers from
a first program number to a second program number, the method
comprises the steps of:
identifying a second physical channel number based on the second
program number, for transmitting a second program having the second
program number therethrough;
determining whether or not the identified second physical channel
number is the same as a first physical channel number which is now
being received;
extracting a program map table packet identifier, corresponding to
the second program number, from a program association table
including the second program number, if it is determined that the
first and the second physical channel numbers are the same;
switching so as to receive the physical channel having the
identified second physical number and simultaneously extracting a
program map table packet identifier, corresponding to the second
program number, from one of the program association tables which
have been transmitted as private data, if it is determined that the
first and the second physical channel numbers are not the same;
extracting an elementary packet identifier, corresponding to the
second program number, from a program map table including the
extracted program map table packet identifier; and
extracting a packet having the extracted elementary packet
identifier from a transport stream.
4. A method for switching programs in a digital broadcasting
wherein, on a transmission side, a physical channel number for
transmitting a program having a program number therethrough is
assigned to a part of the program number and program association
tables of all physical channels are transmitted as private data to
transport streams of all of the physical channels,
and wherein, on a receiving side, in changing program numbers from
a first program number to a second program number, the method
comprises the steps of:
(a) identifying a second physical channel number based on the
second program number for transmitting a second program having the
second program number therethrough based on the second program
number;
(b) determining whether or not the identified second physical
channel number is the same as a first physical channel number which
is now being received;
(c) determining whether or not the physical channel having the
identified second physical channel number satisfies a predetermined
condition if it is determined that the first and the second
physical channel numbers are not the same;
(d) switching so as to receive the physical channel having the
identified second physical channel number, if it is determined that
the physical channel having the second physical channel number does
not satisfy the predetermined condition;
(e) extracting a program map table packet identifier, corresponding
to the second program number, from a program association table
including the second program number;
(f) switching so as to receive the physical channel having the
identified second physical channel number and simultaneously
extracting a program map table packet identifier, corresponding to
the second program number, from one of the program association
tables which have been transmitted as private data, if it is
determined that the physical channel having the second physical
channel number satisfies the predetermined condition;
(g) extracting an elementary packet identifier, corresponding to
the second program number, from a program map table including the
extracted program map table packet identifier; and
(h) extracting a packet having the extracted elementary packet
identifier from a transport stream.
5. A method for switching programs in a digital broadcasting
according to claim 4, wherein the predetermined condition is
whether or not an absolute value representing a difference between
the identified second physical channel number and the first
physical channel number which is now being received is a
predetermined value or less.
6. A method for switching programs in a digital broadcasting
according to claim 4, wherein the predetermined condition is
whether or not the identified second physical channel number is
included in physical channel numbers which have been set
beforehand.
7. A method for switching programs in a digital broadcasting
according to claim 4, wherein the predetermined condition is
whether or not the identified second physical channel number is
included in a plurality of physical channel numbers which have ever
been received.
8. A method for switching programs in a digital broadcasting
according to claim 4, wherein the predetermined condition is
whether or not the identified second physical channel number
belongs to physical channel numbers which are frequently used by a
viewer.
9. A method for switching programs in a digital broadcasting
according to claim 8, wherein the physical channel numbers
frequently used by the viewer are M kinds of physical channel
numbers which have been selected most frequently from L kinds of
physical channel numbers which have ever been selected in changing
program numbers L times, where M and L are natural numbers and M is
equal to or smaller than L.
10. A digital broadcast receiving apparatus for receiving a digital
broadcast by transmitting a physical channel number for
transmitting a program having a program number therethrough as a
part of the program number, comprising:
identification means for identifying a second physical channel
number based on the second program number for transmitting a second
program having a newly set program number or a second program
number therethrough;
determination means for determining whether or not the identified
second physical channel number is the same as a first physical
channel number which is now being received; and
switching means for switching to receive the physical channel
having the identified second physical channel number, if the
determination means determines that the first and the second
physical channel numbers are not the same.
11. A method for switching programs in a digital broadcasting
wherein, on a transmission side, a physical channel number for
transmitting a program having a program number therethrough is
assigned to a part of the program number and a program map table
packet identifier corresponding to the program number in a program
association table is assumed to be a fixed value,
and wherein, on a receiving side, program association tables of all
physical channels are stored into storage means and, in changing
program numbers from a first program number into a second program
number, the method comprises the steps of:
identifying a second physical channel number based on the second
program number for transmitting a second program having the second
program number therethrough;
determining whether or not the identified second physical channel
number is the same as a first physical channel number which is now
being received;
extracting a program map table packet identifier, corresponding to
the second program number, from one of the program association
tables which is stored in the storage means and includes the second
program number, if it is determined that the first and the second
physical channel numbers are the same;
switching so as to receive the physical channel having the
identified second physical channel number and simultaneously
extracting a program map table packet identifier, corresponding to
the second program number, from one of the program association
tables which is stored in the storage means and includes the second
program number, if it is determined that the first and the second
physical channel numbers are not the same;
extracting an elementary packet identifier, corresponding to the
second program number, from a program map table including the
extracted program map table packet identifier; and
extracting a packet having the extracted elementary packet
identifier from a transport stream.
12. A method for switching programs in a digital broadcasting
wherein, on a transmission side, a physical channel number for
transmitting a program having a program number therethrough is
assigned to a part of the program number and a program map table
packet identifier corresponding to the program number in a program
association table is assumed to be a fixed value,
and wherein, on a receiving side, program association tables of
physical channels satisfying a predetermined condition are stored
in storage means and, in changing program numbers from a first
program number to a second program number, the method comprises the
steps of:
(a) identifying a second physical channel number based on the
second program number for transmitting a second program having the
second program number therethrough;
(b) determining whether or not the identified second physical
channel number is the same as a first physical channel number which
is now being received;
(c) determining whether or not the identified second physical
channel number satisfies the predetermined condition if it is
determined that the first and the second physical channel numbers
are not the same;
(d) switching so as to receive the physical channel having the
identified second physical channel number, if it is determined that
the second physical channel number does not satisfy the
predetermined condition;
(e) extracting a program map table packet identifier, corresponding
to the second program number, from a program association table
including the second program number after it has been determined
that the first and the second physical channel numbers are the same
in the step (b) or after the step (d) of switching for receiving
the physical channel having the second physical channel number has
been executed;
(f) switching so as to receive the physical channel having the
identified second physical channel number and simultaneously
extracting a program map table packet identifier, corresponding to
the second program number, from one of the program association
tables which have been stored in the storage means, if it is
determined that the second physical channel number satisfies the
predetermined condition in the step (c);
(g) extracting an elementary packet identifier, corresponding to
the second program number, from a program map table including the
extracted program map table packet identifier; and
(h) extracting a packet having the extracted elementary packet
identifier from a transport stream.
13. A method for switching programs in a digital broadcasting
according to claim 12, wherein the predetermined condition is
whether or not the identified second physical channel number is
included in physical channel numbers which have been set
beforehand.
14. A method for switching programs in a digital broadcasting
according to claim 12, wherein the predetermined condition is
whether or not the identified second physical channel number is
included in a plurality of physical channels numbers which have
ever been received.
15. A method for switching programs in a digital broadcasting
according to claim 12, wherein the predetermined condition is
whether or not the identified second physical channel number
belongs to physical channel numbers which are frequently used by a
viewer.
16. A method for switching programs in a digital broadcasting
according to claim 15, wherein the physical channel numbers
frequently used by the viewer are M kinds of physical channel
numbers which have been selected most frequently from L kinds of
physical channel numbers which have been selected in changing
program numbers L times, where M and L are natural numbers and M is
equal to or smaller than L.
17. A method for switching programs in a digital broadcasting
wherein, on a transmission side, a physical channel number for
transmitting a program having a program number therethrough is
assigned to a part of the program number and a packet identifier
for a program map table on which an identifier of a packet or a
component of the program having the program number is described is
assigned to the other part of the program number,
and wherein, on a receiving side, in changing program numbers from
a first program number to a second program number, the method
comprises the steps of:
identifying a second physical channel number for transmitting a
second program having the second program number therethrough and
the packet identifier of the program map table based on the second
program number;
determining whether or not the identified second physical channel
number is the same as a first physical channel number which is now
being received;
switching so as to receive the physical channel having the
identified second physical channel number if it is determined that
the first and the second physical channel numbers are not the
same;
extracting an elementary packet identifier, corresponding to the
second program number, from a program map table including the
identified program map table packet identifier; and
extracting a packet having the extracted elementary packet
identifier from a transport stream.
18. A digital broadcast receiving apparatus for receiving a digital
broadcast by transmitting a physical channel number for
transmitting a program having the program number therethrough as a
part of the program number and a packet identifier for a program
map table on which a packet identifier of a component of the
program having the program number is described as the other part,
comprising:
identification means for identifying a second physical channel
number for transmitting a second program and program map table
packet identifier of the second program by a newly set program
number of the second program;
determination means for determining whether or not the identified
second physical channel number is the same as a first physical
channel number which is now being received; and
switching means for receiving the physical channel having the
identified second physical channel number, if the determination
means determines that the first and the second physical channel
numbers are not the same.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital broadcast receiving
apparatus and a method for switching programs in digital
broadcasting.
2. Description of the Related Art
In recent years, various activities for standardizing digital
broadcasting are being vigorously carried on in many countries.
Broadcasting systems called "ATV" (advanced television) and DVB
(digital video broadcasting) have seen suggested in the Unites
States and in Europe, respectively, and are under research and
development for being put into practical use within a couple of
years. In Japan, the activities for standardizing digital satellite
broadcasting using a communication satellite have also been
proceeding. All of these broadcasting systems are being developed
based on the MPEG2 standard, which became an international standard
in November 1994.
In digital broadcasting, the number of channels is greatly
increased as compared with that of current broadcasting. However,
the larger the number of channels becomes, the more sophisticated
the procedure for selecting a channel or a program is required to
be. More specifically, since transport streams corresponding to
multiple programs include a large number of individual video and
audio streams to be transmitted, information indicating which
program should be selected from a plurality of programs or
information indicating which packets should be retrieved from the
large number of streams is required. Thus, in the MPEG2 standard,
various kinds of transmission control information required for
receiving a desired program is supposed to be transmitted in the
form of a plurality of additional information tables called "PSI
(program specific information)" tables. There are the following
three kids of PSI tables complying with the MPEG2 standard: a PAT
(program association table); a PMT (program map table); and a CAT
(conditional access table).
A PAT is a table showing a relationship between a program.sub.--
number and a packet ID (PID) specifying a PMT (such a PID is called
a "PMT.sub.-- PID"). A PMT is a table showing a relationship
between a program.sub.-- number and the PIDs of the elements, such
as video elements, audio elements and clock references, composing
the program (such PIDs are called "elementary PIDs"). In this case,
a PID is a number for identifying a packet and is also called a
"packet identifier". The PIDs assigned to video packets and audio
packets are called "elementary PIDs".
In this way, the necessary information is indirectly described
while distributing the information between a PAT and a PMT. This is
because if all the information is described in only one table, the
size of the table becomes too large so that the capacity of the
memory for storing such a large table therein is also
disadvantageously increased and it takes a lot of time to access
the desired information.
A CAT is used in a chargeable broadcasting system or the like, and
is an additional table used by a permitted user for decoding and
reproducing scrambled streams or a table showing a relationship
between the PIDs and EMM (entitled management message) streams.
Furthermore, though it is not defined in the MPEG2 standard, an NIT
(network information table) is defined as a table required for
receiving programs in the DVB standard in Europe. The names of
networks and various transmission parameters are included in an
NIT. An NIT is a table showing a relationship between a program
number and transport stream IDs individually corresponding to a
plurality of physical channels and like relationships. Based on
this table, it is possible to know a correspondence between a
program number and the physical channel number through which the
program is transmitted (or a transport stream ID).
On the other hand, according to the MPEG2 standard, data, the
contents of which are not defined and are to be defined by a user
himself, is called "private data". Private data of a section type
is specifically called a "private section".
It is noted that there is a detailed description of the terms cited
above in ISO/IEC 13818-1, November 1994.
Next, the processing flow executed in a receiving apparatus
(currently under development) for changing program numbers will be
described with reference to FIG. 17. Note that FIG. 17 shows a case
where the propagation path is a satellite.
Assume that a program.sub.-- number=x is now being received and
that signals, transmitted from a transponder (or a radio wave
repeater) having a transponder number n0 selected from a plurality
of transponders provided for a satellite, are now being received
(Step n1). During the receiving, various tables including the
above-described NITs, PATs and PMTs are received and then stored
into a memory.
In this case, it should be noted that a "program number" complying
with the MPEG2 standard corresponds to a channel number in
conventional analog broadcasting and does not correspond to an
individual program such as a news telecast, a sport on-the-spot
telecast and the like.
Next, if a viewer changes the program number to select a
program.sub.-- number=y (at Step n2), a search is performed to
determine whether or not the program.sub.-- number=y is included in
the PAT of the transponder n0 which is now used for receiving, or
whether or not a program having the program.sub.-- number=y is
transmitted from the transponder n0 (at Step n3). In satellite
delivering, the number of a transponder individually corresponds to
a transport stream ID.
In the case where the program.sub.-- number=y is included in the
PAT of the transponder n0, a packet ID of a PMT (or a PMT.sub.--
PID) corresponding to the program.sub.-- number=y is found (at Step
n4); elementary PIDs (EL.sub.-- PIDS) corresponding to the
program.sub.-- number=y are found on the PMT having the PID (at
Step n5); and then video packets, audio packets and program clock
references (PCRs) having the EL.sub.-- PIDs are extracted, thereby
performing video decoding and audio decoding and reproducing the
clocks (at Step n6).
On the other hand, in the case where the program.sub.-- number=y is
not included in the PAT of the transponder n0 which is now used for
receiving, it is searched for on an NIT with which transponder
number (or transport stream ID) the program.sub.-- number=y is
transmitted. Assuming that the program.sub.-- number=y is
transmitted from a transponder having a transponder number n (at
Step n7), the receiving frequency is switched to the frequency of
the transponder n for receiving PATs, PMTs and the like (at Step
n8) so as to return to Step n4. That is to say, a packet ID of a
PMT (or a PMT.sub.-- PID) corresponding to the program.sub.--
number=y is found on the PAT of the transponder n (at Step n4);
elementary PIDs (EL.sub.-- PIDs) corresponding to the
program.sub.-- number=y are found on the PMT having the PID (at
Step n5); and then video packets, audio packets and program clock
references (PCRs) having the EL.sub.-- PIDs are extracted, thereby
performing video decoding and audio decoding and reproducing the
clocks (at Step n6).
The processing flow currently under development for changing
program numbers is generally executed in such a manner as described
above.
However, in such a conventional method for changing program
numbers, the time required for obtaining a packet ID of a PMT (a
PMT.sub.-- PID) greatly differs depending upon whether or not the
program number to be selected is included in the PAT before the
switching or whether or not the above-described process steps n7
and n8 are required to be performed. Accordingly, such a method
adversely gives some restlessness to a viewer.
SUMMARY OF THE INVENTION
According to the present invention, a method for switching programs
in a digital broadcasting is provided. In this method, on a
transmission side, a physical channel number for transmitting a
program having a program number therethrough is assigned to a part
of the program number and on a receiving side, in changing program
numbers from a first program number to a second program number, a
second physical channel number, for transmitting a second program
having the second program number therethrough, is identified based
on the second program number. It is determined whether or not the
identified second physical channel number is the same as a first
physical channel number which is now being received; and if it is
determined that the first and the second physical channel numbers
are not the same, switching is performed for receiving the physical
channel having the identified second physical channel number.
In one embodiment, on a transmission side, a physical channel
number for transmitting a program having a program number
therethrough is assigned to a part of the program number, and on a
receiving side, in changing program numbers from a first program
number to a second program number, the method includes the steps
of: identifying a second physical channel number based on the
second program number, for transmitting a second program having the
second program number therethrough; determining whether or not the
identified second physical channel number is the same as a first
physical channel number which is now being received; switching so
as to receive the physical channel having the identified second
physical channel number, if it is determined that the first and the
second physical channel numbers are not the same; extracting a
program map table packet identifier corresponding to the second
program number from a program association table including the
second program number; extracting an elementary packet identifier
corresponding to the second program number from a program map table
including the extracted program map table packet identifier; and
extracting a packet having the extracted elementary packet
identifier from a transport stream.
In another embodiment, on a transmission side, a physical channel
number for transmitting a program having a program number
therethrough is assigned to a part of the program number and
program association tables of all physical channels are transmitted
as private data to transport streams of all of the physical
channels, and on a receiving side, in changing program numbers from
a first program number to a second program number, the method
includes the steps of: identifying a second physical channel number
based on the second program number, for transmitting a second
program having the second program number therethrough; determining
whether or not the identified second physical channel number is the
same as a first physical channel number which is now being
received; extracting a program map table packet identifier,
corresponding to the second program number, from a program
association table including the second program number, if it is
determined that the first and the second physical channel numbers
are the same; switching so as to receive the physical channel
having the identified second physical number and simultaneously
extracting a program map table packet identifier, corresponding to
the second program number, from one of the program association
tables which have been transmitted as private data, if it is
determined that the first and the second physical channel numbers
are not the same; extracting an elementary packet identifier,
corresponding to the second program number, from a program map
table including the extracted program map table packet identifier;
and extracting a packet having the extracted elementary packet
identifier from a transport stream.
In still another embodiment, on a transmission side, a physical
channel number for transmitting a program having a program number
therethrough is assigned to a part of the program number and
program association tables of all physical channels are transmitted
as private data to transport streams of all of the physical
channels, and on a receiving side, in changing program numbers from
a first program number to a second program number, the method
includes the steps of: (a) identifying a second physical channel
number based on the second program number for transmitting a second
program having the second program number therethrough based on the
second program number; (b) determining whether or not the
identified second physical channel number is the same as a first
physical channel number which is now being received; (c)
determining whether or not the physical channel having the
identified second physical channel number satisfies a predetermined
condition if it is determined that the first and the second
physical channel numbers are not the same; (d) switching so as to
receive the physical channel having the identified second physical
channel number, if it is determined that the physical channel
having the second physical channel number does not satisfy the
predetermined condition; (e) extracting a program map table packet
identifier, corresponding to the second program number, from a
program association table including the second program number; (f)
switching so as to receive the physical channel having the
identified second physical channel number and simultaneously
extracting a program map table packet identifier, corresponding to
the second program number, from one of the program association
tables which have been transmitted as private data, if it is
determined that the physical channel having the second physical
channel number satisfies the predetermined condition; (g)
extracting an elementary packet identifier, corresponding to the
second program number, from a program map table including the
extracted program map table packet identifier; and (h) extracting a
packet having the extracted elementary packet identifier from a
transport stream.
In still another embodiment, the predetermined condition is whether
or not an absolute value representing a difference between the
identified second physical channel number and the first physical
channel number which is now being received is a predetermined value
or less.
In still another embodiment, the predetermined condition is whether
or not the identified second physical channel number is included in
physical channel numbers which have been set beforehand.
In still another embodiment, the predetermined condition is whether
or not the identified second physical channel number is included in
a plurality of physical channel numbers which have ever been
received.
In still another embodiment, the predetermined condition is whether
or not the identified second physical channel number belongs to
physical channel numbers which are frequently used by a viewer.
In still another embodiment, the physical channel numbers
frequently used by the viewer are M kinds of physical channel
numbers which have been selected most frequently from L kinds of
physical channel numbers which have ever been selected in changing
program numbers L times, where M and L are natural numbers and M is
equal to or smaller than L.
According to another aspect of the present invention, a digital
broadcast receiving apparatus for receiving a digital broadcast by
transmitting a physical channel number for transmitting a program
having a program number therethrough as a part of the program
number is provided. The digital broadcast receiving apparatus
includes: identification means for identifying a second physical
channel number based on the second program number for transmitting
a second program having a newly set program number or a second
program number therethrough; determination means for determining
whether or not the identified second physical channel number is the
same as a first physical channel number which is now being
received; and switching means for switching to receive the physical
channel having the identified second physical channel number, if
the determination means determines that the first and the second
physical channel numbers are not the same.
According to still another aspect of the present invention, a
method for switching programs in a digital broadcasting is
provided. In this method, on a transmission side, a physical
channel number for transmitting a program having a program number
therethrough is assigned to a part of the program number and a
program map table packet identifier corresponding to the program
number in a program association table is assumed to be a fixed
value, and on a receiving side, program association tables of all
physical channels are stored into storage means and, in changing
program numbers from a first program number into a second program
number, the method includes the steps of: identifying a second
physical channel number based on the second program number for
transmitting a second program having the second program number
therethrough; determining whether or not the identified second
physical channel number is the same as a first physical channel
number which is now being received; extracting a program map table
packet identifier, corresponding to the second program number, from
one of the program association tables which is stored in the
storage means and includes the second program number, if it is
determined that the first and the second physical channel numbers
are the same; switching so as to receive the physical channel
having the identified second physical channel number and
simultaneously extracting a program map table packet identifier,
corresponding to the second program number, from one of the program
association tables which is stored in the storage means and
includes the second program number, if it is determined that the
first and the second physical channel numbers are not the same;
extracting an elementary packet identifier, corresponding to the
second program number, from a program map table including the
extracted program map table packet identifier; and extracting a
packet having the extracted elementary packet identifier from a
transport stream.
According to still another aspect of the present invention, a
method for switching programs in a digital broadcasting is
provided. In this method, on a transmission side, a physical
channel number for transmitting a program having a program number
therethrough is assigned to a part of the program number and a
program map table packet identifier corresponding to the program
number in a program association table is assumed to be a fixed
value, and on a receiving side, program association tables of
physical channels satisfying a predetermined condition are stored
in storage means and, in changing program numbers from a first
program number to a second program number, the method includes the
steps of: (a) identifying a second physical channel number based on
the second program number for transmitting a second program having
the second program number therethrough; (b) determining whether or
not the identified second physical channel number is the same as a
first physical channel number which is now being received; (c)
determining whether or not the identified second physical channel
number satisfies the predetermined condition if it is determined
that the first and the second physical channel numbers are not the
same; (d) switching so as to receive the physical channel having
the identified second physical channel number, if it is determined
that the second physical channel number does not satisfy the
predetermined condition; (e) extracting a program map table packet
identifier, corresponding to the second program number, from a
program association table including the second program number after
it has been determined that the first and the second physical
channel numbers are the same in the step (b) or after the step (d)
of switching for receiving the physical channel having the second
physical channel number has been executed; (f) switching so as to
receive the physical channel having the identified second physical
channel number and simultaneously extracting a program map table
packet identifier, corresponding to the second program number, from
one of the program association tables which have been stored in the
storage means, if it is determined that the second physical channel
number satisfies the predetermined condition in the step (c); (g)
extracting an elementary packet identifier, corresponding to the
second program number, from a program map table including the
extracted program map table packet identifier; and (h) extracting a
packet having the extracted elementary packet identifier from a
transport stream.
According to still another aspect of the present invention, a
method for switching programs in a digital broadcasting is
provided. In this method, on a transmission side, a physical
channel number for transmitting a program having a program number
therethrough is assigned to a part of the program number and a
packet identifier for a program map table on which an identifier of
a packet or a component of the program having the program number is
described is assigned to the other part of the program number, and
on a receiving side, in changing program numbers from a first
program number to a second program number, the method includes the
steps of: identifying a second physical channel number for
transmitting a second program having the second program number
therethrough and the packet identifier of the program map table
based on the second program number; determining whether or not the
identified second physical channel number is the same as a first
physical channel number which is now being received; switching so
as to receive the physical channel having the identified second
physical channel number if it is determined that the first and the
second physical channel numbers are not the same; extracting an
elementary packet identifier, corresponding to the second program
number, from a program map table including the identified program
map table packet identifier; and extracting a packet having the
extracted elementary packet identifier from a transport stream.
According to still another aspect of the present invention, a
digital broadcast receiving apparatus for receiving a digital
broadcast by transmitting a physical channel number for
transmitting a program having the program number therethrough as a
part of the program number and a packet identifier for a program
map table on which a packet identifier of a component of the
program having the program number is described as the other part is
provided. The digital broadcast receiving apparatus includes:
identification means for identifying a second physical channel
number for transmitting a second program and program map table
packet identifier of the second program by a newly set program
number of the second program; determination means for determining
whether or not the identified second physical channel number is the
same as a first physical channel number which is now being
received; and switching means for receiving the physical channel
having the identified second physical channel number, if the
determination means determines that the first and the second
physical channel numbers are not the same.
According to the present invention, it is possible to shorten the
time required for changing the program numbers while switching
physical channels and reduce a time difference between the case of
switching physical channels and the case of changing program
numbers in one and the same physical channel, so that the
restlessness given to a viewer can be reduced.
In addition, by assigning a physical channel number and a program
map table packet identifier to a part of a program number, it is
possible not only to shorten the time required for changing the
programs but also to save a memory region in a receiving apparatus
in which a program association table is stored.
Thus, the invention described herein makes possible the advantage
of reducing the restlessness given to a viewer by reducing as much
as possible a time difference between the case of changing program
numbers while switching physical channels and the case of changing
program numbers without switching physical channels.
This and other advantages of the present invention will become
apparent to those skilled in the art upon reading and understanding
the following detailed description with reference to the
accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing a configuration for a receiving
apparatus according to the present invention.
FIG. 2 is a diagram showing the assignment of a physical channel
number to a program number.
FIG. 3 is a flow chart for illustrating the operation according to
a first example of the present invention.
FIG. 4 is a flow chart for illustrating the operation according to
a second example of the present invention.
FIG. 5 is a flow chart for illustrating the operation according to
a third example of the present invention.
FIG. 6 is a flow chart for illustrating the operation according to
a fourth example of the present invention.
FIG. 7 is a flow chart for illustrating the operation according to
a fifth example of the present invention.
FIG. 8 is a flow chart for illustrating the operation according to
a sixth example of the present invention.
FIG. 9 is a diagram showing a part of a table storage section
according to a seventh example of the present invention.
FIG. 10 is a flow chart for illustrating the operation according to
the seventh example of the present invention.
FIG. 11 is a diagram showing a part of a table storage section
according to an eighth example of the present invention.
FIG. 12 is a flow chart for illustrating the operation according to
the eighth example of the present invention.
FIG. 13 is a flow chart for illustrating the operation according to
a ninth example of the present invention.
FIG. 14 is a flow chart for illustrating the operation according to
a tenth example of the present invention.
FIG. 15 is a diagram showing the assignment of a physical channel
number and a program map table identifier to a program number
according to an eleventh example of the present invention.
FIG. 16 is a flow chart for illustrating the operation according to
the eleventh example of the present invention.
FIG. 17 is a flow chart for illustrating the operation of a
receiving apparatus according to a conventional example.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, the present invention will be described in detail by
way of illustrative examples with reference to the accompanying
drawings.
FIG. 1 shows a configuration for a digital broadcast receiving
apparatus commonly applicable in the first to the eleventh examples
of the present invention. In the following description of the
preferred embodiments, a propagation path is assumed to be an
artificial satellite.
In FIG. 1, a receiving section 101 receives a radio wave (or bit
streams) from a broadcasting satellite or a communication
satellite; a receiving transponder switching section 102 switches
the satellite transponders used for receiving (hereinafter, such a
transponder will be referred to as a "receiving transponder"); a
demodulation section 103 demodulates the received bit streams; a
channel decoding section 104 performs Viterbi decoding,
deinterleaving, error correction and the like, thereby reproducing
transport packets; a transport stream separation section 105
separates the transport packets based on packet IDs (PIDs) and
table IDs (TIDs); a table storage section 106 stores therein
various kinds of program specific information (PSI) tables such as
NITs, PATs and PMTs described above and private sections; a data
stream storage section 107 stores therein video streams and audio
streams; a clock reproducing section 109 reproduces system clocks
based on a clock reference included in a transport stream; a
control section 108, also functioning as an identification section
and a determination section, controls the receiving transponder
switching section 102, the demodulation section 103, the channel
decoding section 104, the transport stream separation section 105,
the table storage section 106, the data stream storage section 107
and the clock reproducing section 109.
EXAMPLE 1
Hereinafter, a method in accordance with a first example according
to the present invention for switching the programs by the use of
the digital broadcast receiving apparatus having such a
configuration will be described in association with the operation
of the apparatus.
In this example, the assignment pattern of a program number and a
transport stream ID is specified on the transmission side as
follows. That is to say, for example, an assignment pattern shown
in FIG. 2 is used, i.e., the upper four bits out of sixteen bits,
which are assigned to a program.sub.-- number in compliance with
the MPEG2 standard, are assumed to represent the number of a
transponder or a physical channel number for transmitting a program
having the program.sub.-- number.
Moreover, the transponder numbers individually correspond to the
transport stream IDs as shown in Table 1, for example.
TABLE 1 ______________________________________ transport stream ID
transponder number (represented hexadecimally)
______________________________________ 0 0x0000 1 0x0001 2 0x0002 .
. . . . . 15 0x000F ______________________________________
Furthermore, the transport stream IDs, individually corresponding
to the respective transponder numbers, correspond to the program
numbers as shown in Table 2. These relationships are described on
the network information table (NIT) mentioned above.
TABLE 2 ______________________________________ program number
(repre- transport stream ID (re- sented hexadecimally) presented
hexadecimally) ______________________________________ 0x0000 0x0000
0x0001 0x0000 . . . 0x0000 0x0FFF 0x0000 0x1000 0x0001 0x1001
0x0001 . . . 0x0001 0x1FFF 0x0001 . . . . . . 0xF000 0x000F 0xF001
0x000F . . . 0x000F 0xFFFF 0x000F
______________________________________
Next, the processing executed for changing the programs in the
first example will be described with reference to the flow chart
shown in FIG. 3.
It is assumed that a program.sub.-- number x=0x0001 (represented
hexadecimally) is currently being received (at Step n10).
The operation of the receiving apparatus in such a case will be
described with reference to FIG. 1. The demodulation section 103
has demodulated bit streams having a transponder number "0" based
on Tables 1 and 2 and the transport stream separation section 105
has stored a program association table (PAT) having the transponder
number "0" into the table storage section 106. More specifically, a
specific PID (=0x00) is assigned to the PAT (in compliance with the
MPEG2 standard), and the transport stream separation section 105
recognizes this PID and stores the PAT in a region of the table
storage section 106. On this PAT, a PID of a program map table
(PMT) or a PMT.sub.-- PID corresponding to a program.sub.-- number
x is described.
The transport stream separation section 105 recognizes this
PMT.sub.-- PID and stores the PMT in a different region of the
table storage section 106 from the region where the PAT is stored.
The regions of the table storage section 106 where the PAT and the
PMT are to be stored are decided by the control section 108. The
control section 108 reads out elementary PIDs (or video streams and
audio streams) corresponding to the program.sub.-- number x which
is described on the PMT and controls the transport stream
separation section 105 to extract packets having the elementary
PIDs from the transport streams. The control section 108 also reads
out a PCR.sub.-- PID (or a PID of a program clock reference)
corresponding to the program.sub.-- number x which is described on
the PMT and controls the transport stream separation section 105 to
extract a program clock reference (PCR). The video packets and the
audio packets extracted by the transport stream separation section
105 are once stored into the data stream storage section 107 and
then output to a video decoder and an audio decoder, respectively.
The program clock reference (PCR) extracted by the transport stream
separation section 105 is used as a reference for reproducing
system clocks in the clock reproducing section 109.
Referring back to FIG. 3, when the viewer changes the
program.sub.-- number from x to y (.noteq.x) to select the
program.sub.-- number y (at Step n11), the control section 108
checks the upper four bits of the program.sub.-- number y so as to
instantaneously identify to which transponder or transport stream
ID the program.sub.-- number y belongs (at Step n12); determines
whether or not the transport stream ID of the program.sub.-- number
y is the same as the transport stream ID of the program x or
whether or not the number of the selected transponder is the same
as the receiving transponder (at Step n13); and, if the IDs or the
numbers are not the same, controls the receiving transponder
switching section 102, thereby switching the receiving transponders
(at Step n14).
When the receiving transponder is switched to a transponder to
which the program.sub.-- number y belongs, the control section 108
stores a PAT having a new transport stream ID into the table
storage section 106; extracts the PMT.sub.-- PID of the
program.sub.-- number y from the PAT; stores the PMT having this
PMT.sub.-- PID into the table storage section 106 (at Step n15);
finds elementary PIDs (EL.sub.-- PIDs) corresponding to the
program.sub.-- number=y on the PMT having the packet identifier (at
Step n16); and extracts the video packets, the audio packets and
the program clock references (PCRs) having the elementary PIDs,
thereby performing video decoding and audio decoding and
reproducing the clocks (at Step n17).
In the conventional example shown in FIG. 17, how to number the
programs has nothing to do with transponder numbers. However, in
the first example, a transponder number is assigned to the upper
four bits of a program number, so that, in changing the program
numbers while switching the transponders, it is no longer necessary
to perform a search on an NIT to determine to which transponder
number (or transport stream ID) the newly selected program number
belongs. As a result, it is possible to shorten the time required
for changing the program numbers while switching the transponders
by the time during which a transponder corresponding to the program
number is searched for on an NIT as compared with a conventional
example. Consequently, it is possible to reduce a time difference
between a time required for switching the program numbers while
switching the transponders and a time required for switching the
program numbers without switching the transponders, thereby
reducing the restlessness of a viewer.
EXAMPLE 2
Next, a second example of the present invention will be
described.
The fundamental configuration of the digital broadcast receiving
apparatus in the second example is the same as that in the first
example and is shown in FIG. 1.
In this second example, it is also assumed that a transponder
number or a physical channel number is assigned to the upper four
bits of a program number and that the relationship between a
transponder number and a transport stream ID and the relationship
between a transport stream ID and a program number are defined as
shown in Tables 1 and 2, respectively, in the same way as in the
first example.
In the second example, the PATs of all the transponders (a maximum
number of the PATs is 16 in this case) are transmitted in the form
of a private section complying with the MPEG2 standard from the
transmission side. In other words, it is always possible to receive
the PATs of all the transponders irrespective of which transponder
is received.
In this example, the section.sub.-- syntax.sub.-- indicator of the
private section is set to be "1", a transport stream ID is
described on the table.sub.-- id.sub.-- extension and a similar
association between program numbers and PIDs to the PAT is
described on the private.sub.-- data.sub.-- byte.
Next, the processing executed in the case of changing the program
numbers in the second example will be described with reference to
the flow chart shown in FIG. 4.
In the second example, even when a program.sub.-- number x is being
received (at Step n20), the PATs of all the transponders other than
the transponder to which the program.sub.-- number x belongs are
also received in the form of a private section. In the receiving
apparatus shown in FIG. 1, the private section in which these PATs
are described is stored in a region of the table storage section
106 which is decided by the control section 108. The private
section is identified by the transport stream ID described on the
table.sub.-- id.sub.-- extension.
When the viewer changes the program.sub.-- number from x to y
(.noteq.x) to select the program.sub.-- number y (at Step n21), the
control section 108 checks the upper four bits of the
program.sub.-- number y so as to instantaneously identify to which
transponder or transport stream ID the program.sub.-- number y
belongs (at Step n22); determines whether or not the transport
stream ID of the program.sub.-- number y is the same as the
transport stream ID of the program.sub.-- number x (at Step n23);
and, if the IDs are not the same, controls the receiving
transponder switching section 102, thereby switching the receiving
transponders (at Step n24). In the second example, in parallel with
switching the receiving transponders, the control section 108 reads
out a PAT having the transport stream ID (corresponding to the
transponder number) of the program.sub.-- number y, thereby
extracting a PMT.sub.-- PID corresponding to the program.sub.--
number y (at Step n24). In this case, the PAT has been transmitted
in the form of a private section from the transmission side and has
been stored in the table storage section 106.
In the case where the transponder of the program.sub.-- number y is
the same as the transponder of the program.sub.-- number x and it
is not necessary to switch the receiving transponders, the control
section 108 extracts a PMT.sub.-- PID on the PAT (not the private
section) of the transponder of the program.sub.-- number x (at Step
n25). The remaining processing after the control section 108 has
extracted the PMT.sub.-- PID is the same as that of the first
example (at Steps n26 and n27).
In the second example, in the case where it is necessary to switch
the transponders for changing the program numbers, the extraction
of a PMT.sub.-- PID on a PAT and the switching of the transponders
are performed at the same time or in parallel with each other (at
Step n24). Consequently, it is possible to further shorten the time
required for changing the program numbers while switching the
transponders as compared with the first example, thereby further
reducing the restlessness of a viewer.
EXAMPLE 3
Next, a third example of the present invention will be
described.
The fundamental configuration of the digital broadcast receiving
apparatus in the third example is the same as that in the previous
examples and is shown in FIG. 1.
In this third example, it is also assumed that a transponder number
or a physical channel number is assigned to the upper four bits of
a program number and that the relationship between a transponder
number and a transport stream ID and the relationship between a
transport stream ID and a program number are defined as shown in
Tables 1 and 2, respectively, in the same way as in the first
example.
In the third example, the PATs of all the transponders (a maximum
number of the PATs is 16 in this case) are transmitted in the form
of a private section complying with the MPEG2 standard from the
transmission side, in the same way as in the second example.
Next, the processing executed in the case of changing the program
numbers in the third example will be described with reference to
the flow chart shown in FIG. 5.
In the third example, even when a program.sub.-- number x is being
received (at Step n30), the receiving apparatus receives and stores
in the form of a private section the PATs of the transponders,
which are other than the transponder to which the program.sub.--
number x belongs (or of which the transport stream ID=Tx) and have
transponder numbers adjacent to the number of the transponder to
which the program.sub.-- number x belongs. The private section in
which these PATs are described is stored in a region of the table
storage section 106 which is decided by the control section
108.
In this case, an "adjacent transponder" is a transponder of which
the transport stream ID is represented as (Tx.+-.Tp) (where Tp is a
natural number smaller than the total number of the transponders).
Assuming that the total number of the transponders is 16, Tp can be
set in the range from 2 to 5, for example. The value may be set
beforehand by the receiving apparatus or by a viewer following a
manual.
When the viewer changes the program.sub.-- number from x to y
(.noteq.x) to select the program.sub.-- number y (at Step n31), the
control section 108 checks the upper four bits of the
program.sub.-- number y so as to instantaneously identify to which
transponder or transport stream ID the program.sub.-- number y
belongs (at Step n32). Next, as a first determination step, the
control section 108 determines whether or not the transport stream
ID=Ty of the program y is the same as the transport stream ID=Tx of
the program.sub.-- number x (at Step n33). If the IDs are not the
same, as a second determination step, the control section 108
determines whether or not a transponder adjacency reference
.vertline.Ty-Tx.vertline..ltoreq.Tp is satisfied (at Step n34). If
the transponder adjacency reference is satisfied, then the control
section 108 switches the receiving transponders and, in parallel
with switching, reads out a PAT having the transport stream ID=Ty
of the program.sub.-- number y from the table storage section 106,
thereby extracting a PMT.sub.-- PID corresponding to the
program.sub.-- number y, in the same way as in the second example
(at Step n35). On the other hand, if Ty and Tx do not satisfy the
transponder adjacency condition, then the control section 108
switches the receiving transponders (at Step n36) and then receives
a PAT having the transport stream ID=Ty and newly stores the PAT
into the table storage section 106, thereby extracting a PMT.sub.--
PID corresponding to the program.sub.-- number y (at Step n37). The
remaining processing after the control section 108 has extracted
the PMT.sub.-- PID is the same as that of the first example (at
Steps n38 and n39).
In the third example, in the case where it is necessary to switch
the transponders for changing the program numbers, if the newly
selected transponder belongs to the transponders adjacent to the
original transponder, then the extraction of a PMT.sub.-- PID on a
PAT and the switching of the transponders are performed at the same
time or in parallel with each other. Consequently, it is possible
to further shorten the time required for changing the program
numbers while switching the transponders as compared with the first
example.
Furthermore, unlike the second example in which the PATs of all the
transponders are received and stored into a memory, the PATs of the
adjacent transponders are received in the form of a private section
and then stored into a memory in the third example. Consequently,
it is possible to reduce the capacity of a memory as compared with
the second example.
EXAMPLE 4
Next, a fourth example of the present invention will be
described.
The fundamental configuration of the digital broadcast receiving
apparatus in the fourth example is the same as that in the previous
examples and is shown in FIG. 1.
In this fourth example, it is also assumed that a transponder
number or a physical channel number is assigned to the upper four
bits of a program number and that the relationship between a
transponder number and a transport stream ID and the relationship
between a transport stream ID and a program number are defined as
shown in Tables 1 and 2, respectively, in the same way as in the
first example.
In the fourth example, the PATs of all the transponders (a maximum
number of the PATs is 16 in this case) are transmitted in the form
of a private section complying with the MPEG2 standard from the
transmission side, in the same way as in the third example.
Next, the processing executed in the case of changing the program
numbers in the fourth example will be described with reference to
the flow chart shown in FIG. 6.
In the third example, Step n34 or a step of determining whether or
not the transponder of an original program number is adjacent to
the transponder of a newly set program number in the case of
changing the program numbers is provided. In the fourth example,
this Step n34 is replaced by a step of determining whether or not
the transport stream ID of the newly set program number belongs to
the transport stream IDs which have been set beforehand by a viewer
in the receiving apparatus or Step n34.sub.0.
If the transport stream ID of the newly set program number belongs
to the transport stream IDs which have been set beforehand by a
viewer in the receiving apparatus, the control section 108 switches
the receiving transponders and, in parallel with switching, reads
out a PAT, which has the transport stream ID=Ty of the
program.sub.-- number y and has been transmitted in the form of a
private section, from the table storage section 106, thereby
extracting a PMT.sub.-- PID corresponding to the program.sub.--
number y (at Step n35). On the other hand, if the transport stream
ID of the newly set program number does not belong to the transport
stream IDs which have been set beforehand by a viewer in the
receiving apparatus, the control section 108 switches the receiving
transponders (at Step n36) and then receives a PAT having the
transport stream ID=Ty and newly stores the PAT into the table
storage section 106, thereby extracting a PMT.sub.-- PID
corresponding to the program.sub.-- number y (at Step n37). The
remaining processing is the same as that of the third example.
In the fourth example, a process step in the third example of
determining whether or not the transponder of an original program
number is adjacent to the transponder of a newly set program number
in the case of changing the program numbers is replaced by a
process step of determining whether or not the transport stream ID
of the newly set program number belongs to the transport stream IDs
which have been set beforehand by a viewer in the case of changing
the programs. Consequently, it is possible to shorten the time
required for changing the programs while switching from the
transponder to a transponder having any of the transport stream IDs
set by the viewer beforehand and reduce a time difference between a
time required for changing the program with switching the
transponder and a time required for changing the programs without
switching the transponders, thereby reducing the restlessness of a
viewer.
EXAMPLE 5
Next, a fifth example of the present invention will be
described.
The fundamental configuration of the digital broadcast receiving
apparatus in the fifth example is the same as that in the previous
examples and is shown in FIG. 1.
In this fifth example, it is also assumed that a transponder number
or a physical channel number is assigned to the upper four bits of
a program number and that the relationship between a transponder
number and a transport stream ID and the relationship between a
transport stream ID and a program number are defined as shown in
Tables 1 and 2, respectively, in the same way as in the first
example.
In the fifth example, the PATs of all the transponders (a maximum
number of the PATs is 16 in this case) are transmitted in the form
of a private section complying with the MPEG2 standard from the
transmission side, in the same way as in the third example.
Next, the processing executed in the case of changing the program
numbers in the fifth example will be described with reference to
the flow chart shown in FIG. 7.
In the third example, Step n34 or a step of determining whether or
not the transponder of an original program number is adjacent to
the transponder of a newly set program number in the case of
changing the program numbers is provided. In the fifth example,
this Step n34 is replaced by a step of determining whether or not
the transport stream ID of the newly set program number is included
in the transport stream IDs of number K (where K is a natural
number) kinds of different transponders which have recently been
used for receiving or Step n34.sub.1. That is to say, one of the
PATs which has been transmitted in the form of private sections (or
a private section) and has the same transport stream ID as any of
the transport stream IDs of number K kinds of different
transponders which have recently been used for receiving is decided
by the control section 108 and stored into the table storage
section 106. The value of K can be set in the range from 2 to 6,
for example. Alternatively, K may be larger than 6. If the
transport stream ID of the newly set program number is the same as
any of the transport stream IDs of number K kinds of different
transponders which have recently been used for receiving, the
control section 108 switches the receiving transponders and, in
parallel with switching, reads out a PAT, which has the transport
stream ID=Ty of the program.sub.-- number y and has been
transmitted in the form of a private section, from the table
storage section 106, thereby extracting a PMT.sub.-- PID
corresponding to the program.sub.-- number y (at Step n35). On the
other hand, if the transport stream ID of the newly set program
number is not the same as any of the transport stream IDs of number
K kinds of different transponders which have recently been used for
receiving, the control section 108 switches the receiving
transponders (at Step n36) and then receives a PAT having the
transport stream ID=Ty and newly stores the PAT into the table
storage section 106, thereby extracting a PMT.sub.-- PID
corresponding to the program.sub.-- number y (at Step n37). The
remaining processing is the same as that of the third example.
In the fifth example, a process step in the third example of
determining whether or not the transponder of an original program
number is adjacent to the transponder of a newly set program number
in the case of changing the program numbers is replaced by a step
of determining whether or not the transport stream ID of the newly
set program number belongs to the transport stream IDs of number K
kinds of different transponders which have recently been used for
receiving in the case of changing the program numbers.
Consequently, it is possible to shorten the time required for
changing the programs while switching the transponder to any of the
number K of transponders which have recently been used for
receiving and reduce a time difference between a time required for
changing the programs with switching the transponders and a time
required for changing the programs without switching the
transponders, so that the restlessness of a viewer can be
reduced.
EXAMPLE 6
Next, a sixth example of the present invention will be
described.
The fundamental configuration of the digital broadcast receiving
apparatus in the sixth example is the same as that in the previous
examples and is shown in FIG. 1.
In this sixth example, it is also assumed that a transponder number
or a physical channel number is assigned to the upper four bits of
a program number and that the relationship between a transponder
number and a transport stream ID and the relationship between a
transport stream ID and a program number are defined as shown in
Tables 1 and 2, respectively, in the same way as in the first
example.
In the sixth example, the PATs of all the transponders (a maximum
number of the PATs is 16 in this case) are transmitted in the form
of a private section complying with the MPEG2 standard from the
transmission side, in the same way as in the third example.
Next, the processing executed in the case of changing the program
numbers in the sixth example will be described with reference to
the flow chart shown in FIG. 8.
In the third example, Step n34 or a step of determining whether or
not the transponder of an original program number is adjacent to
the transponder of a newly set program number in the case of
changing the program numbers is provided. In the sixth example,
Step n34 is replaced by a step of determining whether or not the
transport stream ID of the newly selected program number is
included in the transport stream IDs of the transponders which are
frequently used by a viewer or Step n34.sub.2.
The transport stream IDs of the transponders which are frequently
used by a viewer are assumed to be a number M of transport stream
IDs (where M is a natural number). The number M of transport stream
IDs have been selected most frequently from a number L of transport
stream IDs (where L is also a natural number) of the same number of
transponders, which have been set in changing the program numbers L
times. For example, the values of L and M may be 40 and 5,
respectively. However, the value of M may be set at any arbitrary
number so long as the number does not exceed the total number of
the transponders or the number of the receivable physical
channels.
One of the PATs transmitted in the form of a private section which
has the same transport stream ID as any of the transport stream IDs
of the transponders frequently used by a viewer is decided and then
stored into the table storage section 106 by the control section
108. If the transport stream ID of the newly set program number is
the same as any of the transport stream IDs of the transponders
which are frequently used by a viewer, the control section 108
switches the receiving transponders and, in parallel with
switching, reads out a PAT, which has the transport stream ID=Ty of
the program.sub.-- number y, from the table storage section 106,
thereby extracting a PMT.sub.-- PID corresponding to the
program.sub.-- number y (at Step n35). On the other hand, if the
transport stream ID of the newly set program number is not the same
as any of the transport stream IDs of the transponders which are
frequently used by a viewer, the control section 108 switches the
receiving transponders (at Step n36) and then receives a PAT having
the transport stream ID=Ty and newly stores the PAT into the table
storage section 106, thereby extracting a PMT.sub.-- PID
corresponding to the program.sub.-- number y (at Step n37). The
remaining processing is the same as that of the third example.
In the sixth example, a process step in the third example of
determining whether or not the transponder of an original program
number is adjacent to the transponder of a newly set program number
in the case of changing the program numbers is replaced by a step
of determining whether or not the transport stream ID of the newly
set program number belongs to the transport stream IDs of the
transponders which are frequently used by a viewer. Consequently,
it is possible to shorten the time required for changing the
program numbers while switching the transponder to any of the
transponders which are frequently used by a viewer and reduce a
time difference between a time required for changing the program
numbers with switching the transponders and a time required for
changing the program numbers without switching the transponders, so
that the restlessness of a viewer can be reduced.
EXAMPLE 7
Next, a seventh example of the present invention will be
described.
The fundamental configuration of the digital broadcast receiving
apparatus in the seventh example is the same as that of the
previous examples and is shown in FIG. 1. In this seventh example,
it is also assumed that a transponder number or a physical channel
number is assigned to the upper four bits of a program number and
that the relationship between a transponder number and a transport
stream ID and the relationship between a transport stream ID and a
program number are defined as shown in Tables 1 and 2,
respectively, in the same way as in the first example.
Hereinafter, a method in the seventh example for switching the
programs by the use of the digital broadcast receiving apparatus
having the configuration described in the first example will be
described in association with the operation of the apparatus.
First, when a power is initially supplied to the receiving
apparatus, the control section 108 makes the receiving transponder
switching section 102 sequentially switch the received frequencies
in the demodulation section 103, thereby sequentially receiving all
of the physical channels. Then, the transport stream separation
section 105 sequentially extracts the program association tables
(PATs) of the respective physical channels from the transport
streams transmitted through the respective physical channels and
then stores the PATs into the table storage section 106. The
control section 108 extracts an NIT from a transport stream and
then stores the NIT into a region in the table storage section
106.
More specifically, since a specific PID (=0x00 represented
hexadecimally) is assigned to each PAT (in compliance with the
MPEG2 standard), and a transport.sub.-- stream.sub.-- id is
assigned to the PAT of a transport stream in each physical channel,
the transport stream separation section 105 stores the PAT into a
predetermined region in the table storage section 106 based on
these values.
FIG. 9 shows how the PATs are stored in the table storage section
106. As shown in FIG. 9, a plurality of PATs corresponding to the
respective physical channels are stored in the individual regions
of the table storage section 106 as indicated by PAT.sub.-- 1,
PAT.sub.-- 2, . . . and PAT.sub.-- N. In this case, N is the total
number of the physical channels or the number of the satellite
transponders if the propagation path is a satellite.
Next, the processing executed in the case of changing the program
numbers in the seventh example will be described with reference to
the flow chart shown in FIG. 10. In this example, it is assumed
that a program.sub.-- number x=0x0001 (represented hexadecimally)
is now being received (at Step n40).
The operation of the receiving apparatus in such a case will be
described with reference to FIG. 1. The demodulation section 103
has demodulated bit streams having a physical channel number=0
(transport stream ID=0) based on Tables 1 and 2 and the PATs
(PAT.sub.-- 1, PAT.sub.-- 2, . . . and PAT.sub.-- N) of all of the
physical channels are stored in the table storage section 106, as
mentioned above. Herein, the PAT of the transport stream which is
now being received is assumed to be PAT.sub.-- x.
On the PAT.sub.-- x, the PID of a program map table (PMT) or a
PMT.sub.-- PID corresponding to a program.sub.-- number x is
described.
The transport stream separation section 105 recognizes this
PMT.sub.-- PID and then stores the PMT in a different region of the
table storage section 106 from the regions where the PAT and the
NIT are stored. The regions in the table storage section 106 where
the PAT and the PMT are stored are decided by the control section
108.
The control section 108 reads out elementary PIDs (or the PIDs of
video streams and audio streams) which correspond to the
program.sub.-- number x and are described on the PMT and controls
the transport stream separation section 105 to extract packets
having the elementary PIDs from the transport streams. The control
section 108 also reads out a PCR.sub.-- PID (or a PID of a program
clock reference) which corresponds to the program.sub.-- number x
and is described on the PMT and controls the transport stream
separation section 105 to extract a program clock reference (PCR).
The video packets and the audio packets extracted by the transport
stream separation section 105 are stored into the data stream
storage section 107 and then output to a video decoder and an audio
decoder, respectively. The program clock reference (PCR) extracted
by the transport stream separation section 105 is used as a
reference for reproducing system clocks in the clock reproducing
section 109.
Referring back to FIG. 10, when the viewer changes the
program.sub.-- number from x to y (.noteq.x) to select the
program.sub.-- number y (at Step n41), the control section 108
checks the upper four bits of the program.sub.-- number y so as to
instantaneously identify to which transponder or transport stream
ID the program.sub.-- number y belongs (at Step n42); determines
whether or not the transport stream ID of the program.sub.-- number
y is the same as the transport stream ID of the program.sub.--
number x or the number of the transponder which is now used for
receiving (at Step n43); and, if the IDs are not the same, controls
the receiving transponder switching section 102, thereby switching
the receiving transponders (at Step n44). In parallel with the
switching of the transponders, the control section 108 identifies
the PAT of the newly selected transport stream which is stored in
the table storage section 106 (herein, this PAT is assumed to be
PAT.sub.-- y) based on the transport stream ID and then extracts a
PMT.sub.-- PID corresponding to the newly selected program number
based on the PAT.sub.-- y (at Step n44).
If the transponder for transmitting a program having the
program.sub.-- number y is the same as the transponder for
transmitting a program having the program.sub.-- number x and it is
not necessary to switch the receiving transponders, the control
section 108 extracts a PMT.sub.-- PID on the PAT (=PAT.sub.-- x) of
the transponder having the program.sub.-- number x.
The control section 108 sets the transport stream separation
section 105 to extract a PMT having the PMT.sub.-- PID which has
been extracted at Step n44 or n45. Following this setting, the
transport stream separation section 105 extracts this PMT. Then,
the control section 108 finds elementary PIDs (EL.sub.-- PIDs) and
a program clock reference PID (PCR.sub.-- PID) corresponding to the
program.sub.-- number=y on the PMT (at Step n46) and extracts the
video packets, the audio packets and the program clock reference
(PCR) of the PCR.sub.-- PID having the elementary PIDs, thereby
performing video decoding and audio decoding and reproducing the
clocks (at Step n47).
In this example, in changing the program numbers while switching
the transponders, the extraction of a PMT.sub.-- PID from a PAT
which has been stored beforehand in the receiving apparatus is
executed at the same time or in parallel with the switching of the
transponders. Consequently, the time required for changing the
programs can be shortened as compared with a conventional example
by the time required for capturing a PAT after switching the
transponders and the time required for extracting a PMT.sub.-- PID
on the captured PAT.
As a result, it is possible to reduce a time difference between a
time required for changing the program numbers while switching the
transponders and a time required for changing the program numbers
without switching the transponders, so that the restlessness of a
viewer can be reduced.
EXAMPLE 8
Next, an eighth example of the present invention will be
described.
The fundamental configuration of the digital broadcast receiving
apparatus in the eighth example is the same as that of the previous
examples and is shown in FIG. 1.
In this eighth example, it is also assumed that a transponder
number is assigned to the upper four bits of a program number and
that the relationship between a transponder number and a transport
stream ID and the relationship between a transport stream ID and a
program number are defined as shown in Tables 1 and 2,
respectively, in the same way as in the first example.
In this eighth example, it is assumed that a viewer sets the
physical channels, through which PATs of transport streams are
received into the receiving apparatus, when power is initially
supplied to the receiving apparatus. The number of the physical
channels set by the viewer for receiving the PATs into the
receiving apparatus therethrough is assumed to be m, where m is a
natural number equal to or smaller than the total number N of the
physical channels (or the total number of the transponders). For
example, the viewer may set his favorite physical channel number(s)
or transport stream ID(s) in this case. The control section 108 of
the receiving apparatus sequentially stores the PAT (PID=0x00) of
one transport stream or the PATs of a plurality of transport
streams, corresponding to the physical channel number(s) set by the
viewer, into the table storage section 106 while changing the
received frequencies. FIG. 11 shows the PAT storage region in the
table storage section 106 in such a case. In this eighth example,
PAT.sub.-- 1, . . . and PAT.sub.-- m are the PATs of the physical
channels set by the viewer.
Next, the processing executed in the case of changing the program
numbers in the eighth example will be described with reference to
the flow chart shown in FIG. 12.
When the viewer changes the program.sub.-- number from x to y
(.noteq.x) to select the program.sub.-- number y (at Step n51), the
control section 108 checks the upper four bits of the
program.sub.-- number y so as to instantaneously identify to which
transponder or transport stream ID the program.sub.-- number y of
the program belongs (at Step n52). Next, as a first determination
step, the control section 108 determines whether or not the
transport stream ID=Ty of the program.sub.-- number y is the same
as the transport stream ID=Tx of the program.sub.-- number x (at
Step n53). If the IDs are not the same, as a second determination
step, the control section 108 determines whether or not the
transport stream ID of the program.sub.-- number y is the same as
the transport stream ID of any of the physical channels which have
been set beforehand by the viewer in the receiving apparatus (at
Step n54.sub.0).
If it is determined in the second determination step that the
transport stream ID=Ty of the newly set program.sub.-- number y is
the same as the transport stream ID of any of the physical channels
which have been set beforehand by the viewer in the receiving
apparatus, then the control section 108 switches the receiving
transponders and, in parallel with switching, extracts a PMT.sub.--
PID corresponding to the program.sub.-- number y from the
PAT.sub.-- y stored in the table storage section 106 (at Step
n55).
On the other hand, if it is determined in the second determination
step that the transport stream ID=Ty of the newly set
program.sub.-- number y is not the same as the transport stream ID
of any of the physical channels which have been set beforehand by
the viewer in the receiving apparatus, then the control section 108
switches the receiving transponders (at Step n56) and then receives
a PAT having the transport stream ID=Ty (at Step n57) and newly
stores the PAT in the table storage section 106, thereby extracting
a PMT.sub.-- PID=Py corresponding to the program.sub.-- number y
(at Step n58). The remaining processing is the same as that of the
first example.
In the eighth example, in the case where it is necessary to switch
the transponders for changing the program numbers, if the transport
stream ID of a newly set program number belongs to the physical
channel numbers (or transport stream IDs) which have been set
beforehand by the viewer in the receiving apparatus, the extraction
of a PMT.sub.-- PID on a PAT and the switching of the transponders
are performed at the same time or in parallel with each other. As a
result, the time required for switching the programs between the
physical channels which have been set by the viewer in the
receiving apparatus can be shortened as compared with a
conventional example and a difference between the time required for
changing the programs while switching the transponders and a time
required for changing the programs without switching the
transponders can be reduced, thereby reducing the restlessness of
the viewer.
Furthermore, in the eighth example, unlike the seventh example in
which the PATs of all of the physical channels are stored into the
table storage section 106, only the PATs of the transport stream
IDs of the physical channels set by the viewer are stored into the
table storage section 106, so that the memory capacity of the table
storage section 106 can be reduced as compared with the seventh
example.
EXAMPLE 9
Next, a ninth example of the present invention will be
described.
The fundamental configuration of the digital broadcast receiving
apparatus in the ninth example is the same as that of the previous
examples and is shown in FIG. 1.
In this ninth example, it is also assumed that a transponder number
is assigned to the upper four bits of a program number and that the
relationship between a transponder number and a transport stream ID
and the relationship between a transport stream ID and a program
number are defined as shown in Tables 1 and 2, respectively, in the
same way as in the first example.
Next, the processing executed in the case of changing the program
numbers in the ninth example will be described with reference to
the flow chart shown in FIG. 13.
In the eighth example, Step n54.sub.0 or a step of determining
whether or not the transport stream ID of the newly set program
number in the case of changing the program numbers belongs to the
transport stream IDs of the physical channels which have been set
beforehand by the viewer in the receiving apparatus is provided. In
the ninth example, Step n54.sub.0 is replaced by Step n54.sub.1 or
a step of determining whether or not the transport stream ID of the
newly set program number belongs to the transport stream IDs of
number K (where K is a natural number equal to or smaller than N)
kinds of different physical channels which have recently been used
for receiving. The value of K may be set beforehand in the
receiving apparatus or set by a viewer.
First, when a power is initially supplied to the receiving
apparatus, the apparatus is set to receive a transport stream of a
particular physical channel. From then on, every time physical
channels are switched, the PAT of a new transport stream is
sequentially stored into the table storage section 106, thereby
storing the PATs (PAT.sub.-- 1, PAT.sub.-- 2, . . . PAT.sub.-- K)
of number K kinds of different transport stream IDs into the table
storage section 106.
Steps n50 to n53 are the same as those of the eighth example. In
changing the program numbers while switching the transponders (when
Ty is different from Tx), if the transport stream ID of the newly
set program number belongs to the number K kinds of different
transport stream IDs which have recently been received, the control
section 108 switches the transponder to the transponder having the
transport stream ID=Ty and, in parallel with switching, extracts a
PMT.sub.-- PID corresponding to the program.sub.-- number y on the
PAT having the transport stream ID=Ty stored in the table storage
section 106 (at Step n55). On the other hand, if the transport
stream ID of the newly set program number does not belong to the
number K kinds of different transport stream IDs of the
transponders or the physical channels which have recently been used
for receiving, then the control section 108 switches the receiving
transponders (at Step n56) and then receives a PAT having the
transport stream ID=Ty (at Step n57) and newly stores the PAT in
the table storage section 106 in place of the PAT which was stored
least recently.
Then, a PMT.sub.-- PID=Py corresponding to the program.sub.--
number y is extracted (at Step n58). The remaining processing is
the same as that of the eighth example.
In the ninth example, Step n54.sub.0 in the eighth example or a
process step of determining whether or not the transport stream ID
of the newly set program number is the same as the transport stream
ID of any of the physical channels which have been set beforehand
by the viewer in the receiving apparatus is replaced by Step
n54.sub.1 or a process step of determining whether or not the
transport stream ID of the newly set program number belongs to the
number K kinds of different transport stream IDs which have
recently been received. If the transport ID of the newly set
program number belongs to the number K kinds of different physical
channel numbers or transport stream IDs which have recently been
used for receiving, the extraction of a PMT.sub.-- PID on a PAT and
the switching of the transponders are performed at the same time or
in parallel with each other. As a result, the time required for
switching the programs among the number K kinds of physical
channels which have recently been used for receiving can be
shortened as compared with a conventional example and a time
difference between the time required for changing the programs
while switching the transponders and a time required for changing
the programs without switching the transponders can be reduced,
thereby reducing the restlessness of the viewer.
Furthermore, in the ninth example, unlike the seventh example in
which the PATs of all of the physical channels are stored into the
table storage section 106, only the PATs of the number K kinds of
physical channels or transport stream IDs which have recently been
used for receiving are stored into the table storage section 106,
so that the memory capacity of the table storage section 106 can be
reduced as compared with the seventh example.
EXAMPLE 10
Next, a tenth example of the present invention will be
described.
The fundamental configuration of the digital broadcast receiving
apparatus in the tenth example is the same as that of the previous
examples and is shown in FIG. 1.
In this tenth example, it is also assumed that a transponder number
is assigned to the upper four bits of a program number and that the
relationship between a transponder number and a transport stream ID
and the relationship between a transport stream ID and a program
number are defined as shown in Tables 1 and 2, respectively, in the
same way as in the first example.
Next, the processing executed in the case of changing the program
numbers in the tenth example will be described with reference to
the flow chart shown in FIG. 14.
In the eighth example, Step n54.sub.0 or a step of determining
whether or not the transport stream ID of the newly set program
number in the case of changing the program numbers belongs to the
transport stream IDs of the physical channels which have been set
beforehand by the viewer in the receiving apparatus is provided. In
the tenth example, Step n54.sub.0 is replaced by Step n54.sub.2 or
a step of determining whether or not the transport stream ID of the
newly set program number is included in the transport stream IDs of
the physical channels which are frequently used by a viewer.
The transport stream IDs of the physical channels frequently used
by a viewer are assumed to be number M (where M is a natural number
equal to or smaller the total number N of the transponders) kinds
of transport stream IDs which have been selected most frequently
from number L (where L is also a natural number) kinds of transport
stream IDs of the same number of transponders which have been set
in changing the program numbers L times. For example, the values of
L and M may be 20 and 5, respectively. However, the values of L and
M may be set beforehand in the receiving apparatus or set by a
viewer in the receiving apparatus. The PATs of the number M kinds
of transport stream IDs belonging to the transport stream IDs of
the physical channels which are frequently used by the viewer are
determined by the control section 108 and then stored into the
table storage section 106.
Steps n50 to n53 are the same as those in the eighth example. In
changing the program numbers while switching the transponders (when
Ty is different from Tx), if the transport stream ID of the newly
set program number belongs to the number M kinds of transport
stream IDs of the physical channels which are frequently used by
the viewer, the control section 108 switches the transponders and,
in parallel with switching, reads out a PAT having the transport
stream ID=Ty of the program.sub.-- number y from the table storage
section 106, thereby extracting a PMT.sub.-- PID corresponding to
the program.sub.-- number y (at Step n55).
On the other hand, if the transport stream ID of the newly set
program number does not belong to the number M kinds of transport
stream IDs of the transponders or the physical channels which are
frequently used by the viewer, then the control section 108
switches the receiving transponders (at Step n56) and then receives
a PAT having the transport stream ID=Ty and newly stores the PAT
into the table storage section 106, thereby extracting a PMT.sub.--
PID=Py corresponding to the program.sub.-- number y (at Step n57).
The remaining processing is the same as that of the ninth
example.
In the tenth example, Step n54.sub.0 of the eighth example or a
process step of determining whether or not the transport stream ID
of the newly set program number in the case of changing the program
numbers is the same as the transport stream ID of any of the
physical channels which have been set beforehand by the viewer in
the receiving apparatus is replaced by Step n54.sub.2 or a process
step of determining whether or not the transport stream ID of the
newly set program number belongs to the number M kinds of transport
stream IDs of the transponders or the physical channels which are
frequently used by the viewer. If the transport ID of the newly set
program number belongs to the number M kinds of physical channel
numbers or transport stream IDs which are frequently used by the
viewer, the extraction of a PMT.sub.-- PID on a PAT and the
switching of the transponders are performed at the same time or in
parallel with each other. As a result, the time required for
changing the programs while switching the transponder to any of the
transponders which are frequently used by the viewer can be
shortened and a time difference between the time required for
changing the programs while switching the transponders and a time
required for changing the programs without switching the
transponders can be reduced, thereby reducing the restlessness of
the viewer.
In the seventh to the tenth examples, the table storage section 106
is assumed to be formed of a nonvolatile memory. Therefore, it is
assumed that, even if the power supply is turned off, the contents
of the PATs stored in the table storage section 106 are not
erased.
In the first to the tenth examples, the upper four bits of a
program number are assumed to be assigned to a physical channel
number. Alternatively, the physical channel number may be assigned
to J bits (where J is a natural number smaller than the bit width
of the program number) or a part of the program number.
EXAMPLE 11
Next, an eleventh example of the present invention will be
described.
The fundamental configuration of the digital broadcast receiving
apparatus in the eleventh example is the same as that of the
previous examples and is shown in FIG. 1.
In this eleventh example, as shown in FIG. 15, it is assumed that a
transponder number is represented by the upper four bits of a
program number composed of 16 bits in the same way as in the first
to the tenth examples and a PMT.sub.-- PID is represented by the
lower 12 bits of the program number. In this case, the PMT.sub.--
PID is assumed to be temporally fixed. In other words, a PMT.sub.--
PID corresponding to a program number is assumed to be temporally
invariable.
Next, the processing executed in the case of changing the program
numbers in the eleventh example will be described with reference to
the flow chart shown in FIG. 16.
In the eleventh example, when the program.sub.-- number y is
selected at the time of changing the program numbers (at Step n71),
the transport stream ID and the PMT.sub.-- PID of the
program.sub.-- number y are identified instantaneously (at Step
n72). Then, it is determined whether or not the transport stream ID
of the program.sub.-- number y is the same as the transport stream
ID of the program.sub.-- number x or the number of the transponder
which is now used for receiving (at Step n73). If the IDs are not
the same, the receiving transponder switching section 102 is
controlled, thereby switching the receiving transponders (at Step
n74). In this stage, since the PMT.sub.-- PID corresponding to the
program.sub.-- number y has already been identified at Step n72 in
this eleventh example, it is no longer necessary to execute a step
of extracting a PMT.sub.-- PID on a PAT. The remaining processing
after an elementary PIDs have been extracted is the same as that of
the seventh example.
In the eleventh example, since a transponder number is assigned to
the upper 4 bits of a program number composed of 16 bits and a
PMT.sub.-- PID are assigned to the lower 12 bits of the program
number as shown in FIG. 15, it is no longer necessary to execute a
step of extracting a PMT.sub.-- PID from a PAT. Thus, the time
required for changing the programs can be further shortened as
compared with any of the seventh to the tenth examples. Moreover,
since the PAT need not be stored in the table storage section 106
of the receiving apparatus, the memory capacity of the table
storage section 106 can be reduced.
In the eleventh example, a physical channel number is assigned to
the upper 4 bits of a program number composed of 16 bits and a
PMT.sub.-- PID is assigned to the lower 12 bits of the program
number. Alternatively, a physical channel number may be assigned to
P bits of a program number composed of 16 bits and a PMT.sub.-- PID
may be assigned to the remaining Q bits of the program number
(where P and Q are natural numbers equal to or smaller than
16).
It is noted that the same effects can be attained if a transponder
for a satellite broadcasting used in the first to the eleventh
examples is replaced by a physical channel for a digital
terrestrial broadcasting or a digital CATV broadcasting.
In addition, the relationship between a physical channel number (or
a transponder number) and a transport stream ID and the
relationship between a program number and a transport stream ID are
not limited to those shown in Tables 1 and 2, respectively.
Various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the scope
and spirit of this invention. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the
description as set forth herein, but rather that the claims be
broadly construed.
* * * * *